Turbosuperchargers for internal combustion engines provide additional charging air to the engine under specific operating conditions. Turbosuperchargers are frequently driven from the exhaust gases of the internal combustion engine (ICE) itself--see, for example, U.S. Pat. No. 3,462,071 (corresponding to German No. 1,503,581). It has also been proposed to operate the turbosupercharger by an external energy source, typically compressed air, which, preferably, also forms part of the supercharging air when the engine should be supercharged although the energy available from exhaust gases is insufficient to effectively drive the exhaust gas supercharger. For example, upon starting of the engine, and to obtain rapid acceleration of the engine, or to obtain a better operation of the engine under accelerating conditions, compressed air is blown into the compressor housing over a plurality of injection ducts. The injection ducts branch off from a compressed air manifold or distribution chamber, formed within the compressor housing of the supercharger. They are so shaped that they direct a stream of compressed air at an inclination on the vanes or blades of the compressor wheel. Usually, the stream direction is at an inclination towards the outer end regions of the vanes or blades. The compressed air stream generates increased torque in the compressor wheel, which increases the speed thereof.
The compressor wheel of the turbosupercharger is fanned; consequently, the spacing of the blades or vanes from each other is relatively high at the outer edge of the compressor wheel. A portion of the energy of the compressed air stream or blast, from the nozzles, thus is wasted and will be blown off without having a torque-increasing effect. The efficiency of additional compressed air injection devices of this kind can hardly be improved due to the geometry of the compressor wheel of the supercharging turbine.